This invention relates generally to industrial washers for cleaning sheet metal blanks. More particularly, the invention relates to a sheet metal blank washer system having a cleaning cassette that is selectively mounted on a tank, wherein the cassette has a plurality of rollers that cooperate with a spray system to clean sheet metal blanks.
Known washers include a roller system and an integral tank that is fixedly secured below the roller system. The roller system utilizes six rollers, three lower rollers and three upper rollers that are positioned directly on top of the lower rollers, thereby forming three pairs of rollers. The first pair of rollers are the entry rollers, the second pair of rollers are the wash rollers, and the final pair of rollers are the exit rollers. A pre-defined gap exists between each pair of rollers to permit passage of the blank. The wash and exit rollers have substantially the same diameter, while the entry rollers have a diameter that is smaller than the wash and exit rollers. The washer has an inlet opening on one side and an exit opening on the opposite side. The upper and lower entry rollers are positioned adjacent the inlet opening and receive the metal blank to be cleaned and guide the blank into the washer. The center rollers are the wash rollers and are used to scrub the blank as it passes through the entry rollers. The exit rollers are positioned adjacent the exit opening and typically next to the washer rollers. A delivery system may be used to coat the metal blanks with lubricity film. A separate spray system is positioned between the entry rollers and exit rollers. The spray system includes a plurality of spray nozzles that inject a wash solution, often with a lubricity coating therein, onto the metal blank to assist in cleaning the blank. In one known washer, an air cylinder is operatively connected to the exit rollers to exert a predetermined pressure in pounds per linear inch (PLI) upon the metal blank as it is passed through the rolls to leave a predetermined amount of coating on the metal blank. In another known system, the wash rollers and exit rollers are supported by a back-up roller system that includes short steel rollers to exert a predetermined pressure on the metal blank to coat the blank. Both the lower and upper rollers are motor driven and are operatively connected to a motor by means of a complex chain drive.
However, known six roller washers have been found to be undesirable for a number of reasons. First, previous known washers have been relatively large, are quite heavy and therefore are not provided with a transport means to enable movement of the washer system to different locations within a manufacturing plant. In addition, the washer systems have been found to produce an inconsistent and uneven film coating thickness on the sheet metal blanks, thereby reducing the cleaning effectiveness of the washer. The chain driven rollers have also been found to be excessively noisy and difficult to disassemble in the event of washer failures or when routine maintenance is required. Moreover, the complexity of known roller systems require constant maintenance. For example, the rollers are not readily accessible when redressing is desired. Instead, to access the rollers, the entire washer much be disassembled. Such activity results in excessive manufacturing down time and loss revenue. Requiring washer disassembly even for routine maintenance may also result in unwanted component movement and even component loss or damage.
Accordingly, there is a need for a washer system that has fewer components, provides improved cleaning, allows for quick disassembly and accessibility to the internal components of the washer for routine maintenance and provides protection against undesirable component movement, loss, or damage
In accordance with the present invention, there is provided an improved sheet metal washer system having a selectively removable washer cassette member, entry and exit rollers, an integral cleaning spray system for delivering cleaning fluid to metal blanks passing through the washer cassette, and a contaminated fluid storage tank. An optional integral spray system for delivering film coatings may also be provided. The cassette member includes a number of machine components that are fixedly secured together to make up a cassette frame member. The frame member is covered with a metallic skin, preferably constructed of stainless steel for durability. The skin further includes hinged access doors positioned on both sides of the washer. Preferably, each side of the washer includes an upper hinge door that swings upwardly and a lower hinge door that swings downwardly. The hinged access doors advantageously provide access to the interior of the washer unit for routine maintenance or repair in the event of washer failures. The top surface of the washer is also provided with a hinged access door that lifts upward to permit easy access to the interior of the washer. See-through end plates are preferably removably connected to either end of the washer to permit easy monitoring of the mechanisms used to operate the washer and the bearing ends of the entry and exit rollers. The cassette further has an open bottom that cooperates with an open tank top when the cassette member is positioned on top of the tank to collect the contaminated fluid and debris being cleaned off of the metal blanks.
The tank preferably includes upwardly projecting locating pins that are received within locating apertures formed on a bottom surface of the cassette to insure proper positioning of the cassette onto the tank. The tank further includes a filter system that segregates the collected debris from the contaminated fluid such that the cleaning fluid may be recirculated into the cleaning spray system via intake manifolds that extend through one side of the cassette housing, to be explained below in further detail. It is preferred that the tank be provided with wheels to permit allow for easy maneuverability of the washer system.
The cassette is selectively removable from the tank and may be substituted with an identical cassette to allow for off-line periodic maintenance or failure, while reducing washer system downtime. Accordingly, the top of the washer cassette is provided with heavy-duty eyebolts that are connectable to lifting chains to permit selective lift-off of the washer by a crane or other suitable lifting mechanism.
In accordance with one aspect of the invention, the cassette has an inlet opening for receiving the metal blank and an outlet opening for ejecting the metal blank after it has been cleaned. The upper and lower hinged doors define the inlet and outlet openings, respectively. Provided within the cassette are four cleaning rollers, each of the rollers having substantially larger diameters than known washers such that the rollers do not require back-up support rollers. By reducing the cleaning rollers from six to four while simultaneously maintaining and often increasing blank cleanliness, as discussed below, a significant reduction in the number of washer system components on the order of fifty percent (50%) is achieved. The reduction in the number of washer components advantageously lowers both production and maintenance costs, as well as washer complexity.
The four cleaning rollers include two lower rollers and two upper rollers, with the upper rollers being positioned directly over the lower rollers. One pair of upper and lower rollers are positioned adjacent to the inlet opening and define the entry rollers that initially receive the metal blank to be cleaned. The second pair of upper and lower rollers define the exit rollers and are positioned adjacent to the outlet opening.
In accordance with an aspect of the invention, the entry rollers are operatively connected to first air cylinders to provide a first predetermined pressure in pounds per linear inch (PLI) to the blank to properly clean the metal blank by delivering cleaning fluid under high pressure. Preferably, the PLI exerted by the entry rollers is approximately 100 PLI. The entry rollers are fiber coated and have a first predetermined durometer (preferably less than 80 durometer) to give the roller a spongy consistency to agitate dirt and debris from the metal blank. Independently of the advantage provided by agitating dirt and debris for easier removal by the cleaning spray system, in practice it has been found that approximately 20% of the mill oil is directly removed by the entry rollers as the blank passes between them. The exit rollers are connected to second air cylinders to exert a second predetermined pressure PLI to the blank to properly remove the cleaning fluid and dry the metal blank. Preferably, the PLI exerted by the exit rollers is approximately 100-175 PLI. The exit rollers are fiber coated and have a second predetermined durometer that is greater than the first predetermined durometer of the entry rollers to dry the metal blank by a squeegee action as it passes between exit rollers. By providing air cylinders for both the entry and exit rollers, the PLI of the rollers is increased over prior art designs, enabling both water and oil based cleaning agents to be employed. Oil based cleaners require a higher PLI than water based cleaning agents. Positioned adjacent to the inlet and exit openings are a plurality of small guide rollers that guide the metal blank between the upper and lower rollers. Preferably, the guide rollers are positioned on a support bar that is secured to the lower hinge door on the entry and exit sides of the washer. Alternatively, the guide rollers may be positioned on a support bar that is connected to an end of the cassette frame.
The rollers are connected to bearing housings on each end of the washer cassette. A drive end of the washer cassette is positioned adjacent to a drive motor and an idle end is positioned adjacent a filter system. The distal ends of the rollers that are connected to the drive end of the washer cassette are connected to the bearing housings by means of non-expandable bearings. The distal ends of the rollers that are connected to the idle end of the washer cassette are connected to the bearing housings by means of expandable bearings that allow for a small degree of expansion of the rollers due to the heat generated by the washer system components.
The lower entry and exit rollers are each provided with an extended shaft on a drive end of the rollers that has a key member for connecting to a shaft drive bearing. A motor drive is positioned on the drive end of the washer, below the cassette unit on a support platform that is preferably integral with the tank. The motor drive includes an outwardly extending input shaft that is connected to a motor drive bearing. A selectively removable timing belt is connected to the motor drive bearing and shaft drive bearings to drive the lower entry and exit rollers. The upper entry and exit rollers, when in an operating position, are positioned in contact with one another such that the upper entry and exit rollers are friction driven by the lower rollers, thereby reducing drive components and simplifying the drive mechanism. An extremely tight fit for metal blank passage is also provided, thereby helping to maximize blank cleanliness. It is the spongy or selectively deformable nature of the rollers that permits the metal blank to pass between them since the outer surfaces of each roller is in contact with its mating roller. Once a blank passes, each roller returns to its non-deformed shape.
Further, disassembly of the drive mechanism is quickly and easily achieved by removing the timing belt. It is preferred that the drive end of the washer includes a recessed area in which the shaft drive bearings are located. The input shaft extends into the recessed area and has the drive shaft bearing positioned thereon. The removable see-through end plate is provided with an aperture for receiving the input shaft and the end plate is positioned over the recessed area to protect the drive mechanism from damage while permitting visibility of the drive assembly to monitor its operation.
In accordance with a further aspect of the invention, there is provided a safety lock on both ends of the washer. The safety lock is a pivoting spring loaded, pneumatically controlled member. The safety lock has an inverted T-shape and includes a pivoting end that is provided with apertures for receiving a pivoting shaft. Support arms are positioned opposite the pivoting end. The pivoting shaft is connected to an input arm that is operatively connected to an air cylinder. When the washer is shut off, the safety lock is automatically pivoted outwardly and the upper rollers are raised by air cylinders away from the lower rollers. Next, the safety lock is pivoted inwardly between the upper and lower rollers and locked into position, such that the support arms support stub ends of the upper rollers. When engaged, the safety lock advantageously provides clearance between the upper and lower rollers to permit safe and easy access to clean or maintain the interior of the washer. The safety lock is also utilized when transporting the cassette to insure that the rollers do not rub against one another during transport causing surface cuts or scratches, thereby prolonging wear life of the rollers.
The cassette further preferably includes an integral cleaning spray system. The cleaning spray system includes upper and lower manifolds that are fluidly connected to the filter system to introduce cleaning fluid to the metal blank. The upper manifold is positioned between the upper rollers and includes a plurality of fluid nozzles being downwardly directed at an angle at the nip (the roller contact portion on the metal blank) of the upper rollers. Preferably, each of the nozzles are equally spaced on either side of the manifold to provide uniform distribution of the cleaning fluid. Extending downwardly from the upper manifold are a plurality of small rollers that are used to guide the metal blank from the entry rollers to the exit rollers. Similarly, the lower manifold is positioned between the lower rollers and includes a plurality of fluid nozzles being upwardly directed at an angle at the nip of the lower rollers. Preferably, each of the nozzles are equally spaced on either side of the lower manifold to provide uniform distribution of the cleaning fluid. The nozzles preferably spray the metal blank at a predetermined rate of fluid per linear inch on both the upper and lower rollers. Extending upwardly from the lower manifold are a plurality of small rollers that cooperate with the rollers of the upper manifold to guide the metal blank from the entry rollers to the exit rollers. The upper and lower manifolds are secured to the idle end of the washer cassette and have outwardly extending inlets that fluidly connect to the filter unit that is integral with the tank by conventional hoses. To provide easy maintenance of the manifolds, it is preferred that the manifold be secured to the idle end of the washer cassette by bolts or other removable fasteners such that the manifolds can be slid out of the cassette quickly and easily.
In accordance with another aspect of the invention, the washer cassette further includes an optional integral exit spray system. The exit spray system is used to provide precise and controlled film coatings on the clean metal blank after it exits from the exit rollers. The exit spray system includes a plurality of nozzles positioned on a support member and connected to the cassette frame member, adjacent to the exit rollers so as to be between the exit rollers and the exit opening. Each nozzle is provided with separate fluid and/or air supply lines such that each nozzle may be independently controlled, either manually or automatically, to deposit film coating on predetermined zones, independently on the top and bottom of the metal blank, thereby conserving film coating.
The washer cassette further desirably includes two air and fluid connection plate assemblies mounted on the entry and exit sides of the washer cassette that have a plurality of air and fluid line connectors and at least one electronic connector plate. The air and fluid connection plates allow for quick one-step connect and disconnect of all air and fluid lines. Similarly, the electronic connector plate provides for a similar quick one-step connect and disconnect of all electronics required to operate the washer system.
Each air and fluid connection plate assembly preferably includes a mounted connection plate and a mating removable connection plate. The mounted connection plate has a plurality of outwardly extending mounting pegs and a plurality of air and fluid line connectors that are operatively connected to the washer components. The removable connection plate has a plurality receiving apertures and a plurality of air and fluid line connectors that are operatively connected to air and fluid lines. The air and fluid line connectors of the mounted connection plate selectively mate to the connectors of the removable plate. Further, the receiving apertures of the removable plate receive the mounting pegs of the mounted connection plate to secure the connection plate assembly together. Preferably, the removable connection plate is pivotally mounted by a support arm to the tank assembly and includes lever arms to selectively lock and unlock the removable connection plate from the mounted connection plate. To disassemble the connection plate, the lever arms are rotated from a locked position to an unlocked position and the removable connection plate, still with all the air and fluid lines connected thereto, is pulled away from the mounted connection plate. The support arm carries the removable connection plate and is pivoted away from the washer cartridge. Thus, the air and fluid lines may be quickly and easily removed from the washer cassette in one motion. It may just as easily be secured during assembly.
The electronic connector plate is preferably a Harding plate that receives a plug-in fitting within an electronic receiver mounted in the electronic plate to allow for one step assembly/disassembly of the electronic components.
In accordance with another aspect of the invention, the interior of the washer cassette is provided with internal flashing mounted to the interior of the washer cassette on the idle and drive ends, around the distal ends of the rollers. The flashing serves to retain the cleaning fluid within the cassette and to protect the bearings of the rollers from damage.
An optional mist collector system may further be provided for the washer system. The mist collector system is preferably a conventional mist collector that is advantageously integrated within the interior of the washer cassette. The mist collector includes ductwork built into the interior of the washer cassette to remove volatile compounds from the interior of the washer cassette, thereby providing a safer working environment.